Bulletin of Environmental Contamination and Toxicology最新文献

The water in the coastal lagoons of the Tramandaí River Basin (TRB) in southern Brazil is affected by domestic, industrial, and agricultural effluents. The towns within the TRB experience significant population surges during peak vacation periods, which may further impact water quality. The micronucleus (MN) test is a useful tool for detecting genotoxic effects induced by pollutant mixtures and can serve as an indicator of water quality. This study aimed to evaluate the temporal variation in genotoxic potential and fecal contamination of water samples from four coastal lagoons within the TRB. Water sampling was conducted across four periods in the Cidreira, Fortaleza, Gentil, and Tramandaí lagoons. Specimens of Astyanax jacuhiensis were exposed to water samples and a negative control for 96 h in laboratory conditions. The frequencies of MN and other nuclear abnormalities (NA) were analyzed in the erythrocytes of the fish. Thermotolerant coliforms were assessed as an indicator of fecal contamination. Significant differences were noted during the summer season, with higher MN frequencies observed in the Gentil lagoon and increased NA frequencies in both the Gentil and Cidreira lagoons compared to the control group. During warmer periods, thermotolerant coliform counts exceeded the limits established by Brazilian legislation for recreational use in the Tramandaí, Gentil, and Cidreira lagoons. These results indicate temporal variations in fecal contamination and water genotoxicity in the TRB lagoons, with the highest values recorded in summer likely linked to increased tourism in the region.

Benzene is a highly volatile monoaromatic hydrocarbon and genotoxic carcinogen. In Brazil, it is considered a priority for the National Health System. However, although this compound is targeted by health surveillance in Brazil, scarce data are available on occupational or environmental exposure. This review contributes to an overview regarding benzene levels in the second-largest metropolis in Southeastern Brazil, Rio de Janeiro, and associated risks. A decreasing trend has been noted in the city of Rio de Janeiro, in the last decades, due to more stringent vehicular emission legislations and advances in vehicular technology, although adulterated gasoline is still a concern. Future actions regarding reductions of benzene emissions in the city include regulatory and surveillance programs concerning adulterated gasoline, substitution of raw materials to reduce benzene input to production processes, implementing changes in operating conditions to minimize benzene formation or volatilization and equipment modification to avoid benzene escaping into the environment. Finally, the increasing use and further construction of alternative transportation can significantly contribute to lowering benzene emissions in Rio de Janeiro and other metropolis worldwide and should be implemented as soon as possible.

Research on emerging micro-pollutants (EMPs) in Indonesia is scarce. Studies indicate that even at relatively low concentrations (µg/L), these substances pose health risks to aquatic biota. This study aimed to identify EMPs in septic tanks and the Surabaya River and assess the influence of social factors such as habits and sanitation levels. Solid-phase extraction (SPE) and High-Performance Liquid Chromatography (HPLC) were used to determine EMPs concentrations in samples. SPE and HPLC were selected for their high sensitivity, selectivity, and efficiency, with SPE enabling sample pre-concentration and purification, while HPLC ensured precise separation and quantification of trace contaminants. The results showed high paracetamol levels (15.54 mg/L) in septic tanks and significant caffeine concentrations (10.31 mg/L) in the Surabaya River. This trend was linked to residents' habit of urinating on bathroom floor drains instead of using toilets, allowing contaminants to flow into drainage systems and the river. Societal consumption habits influenced the types of EMPs in urine, with high caffeine concentrations attributed to the widespread consumption of over-the-counter medications and beverages such as tea and coffee. The lack of regulations on pollutant concentrations in Indonesian rivers increases the risk of contaminants entering clean water treatment systems. Given these findings, stricter monitoring and comprehensive regulations are urgently needed to mitigate potential public health risks and environmental impacts.

Environmental pollution, particularly in aquatic ecosystems, poses a major global threat. The Ganga River, vital to millions, suffers from severe contamination despite multiple remediation efforts. Bioremediation, especially enzyme-mediated approaches, offers an eco-friendly and efficient alternative to conventional methods. This study utilizes metagenomic reads to identify bioremediating enzymes, their host microorganisms, target pollutants, and enzyme abundance at two Ganga sites: Nawabganj, Kanpur (highly polluted), and Below Farakka Bridge, West Bengal (less polluted). In-silico analysis was conducted using RemeDB for enzyme identification and MG-RAST for microbial abundance. Enzyme abundance was determined by integrating microbial profiles with the RemeDB enzyme database. Key enzymes identified include Phenylacetaldehyde dehydrogenase (plastic), Biphenyl dioxygenase (hydrocarbons), and Catechol 1,2-dioxygenase (dyes). Results indicate higher bioremediating enzyme diversity in the more polluted Nawabganj site. The findings highlight the potential of native enzymes for pollutant degradation and support further exploration for environmental cleanup strategies.

The Amazon hosts the world's richest biodiversity but faces increasing anthropogenic pressures that threaten ecosystem health. To evaluate aquatic pollution impacts at molecular and biochemical levels, we analyzed DNA methylation, gene expression and oxidative stress biomarkers in gill, liver, and muscle tissues of the fish Geophagus surinamensis collected from Breves (reference), Abaetetuba, and Barcarena (industrial area). Individuals from Abaetetuba exhibited the strongest responses, with global hypermethylation in liver and muscle, decreased expression of dnmt1, dnmt3b, and tet2, and altered GST and LPO levels. Barcarena samples also showed increased methylation but milder transcriptional and biochemical changes, likely due to contaminant dispersion by Pará River hydrodynamics. The liver was the most responsive organ, reflecting its detoxification role. Overall, these findings demonstrate that pollution in Barcarena significantly affects nearby aquatic environments, highlighting the value of epigenetic and oxidative stress biomarkers as sensitive tools for environmental monitoring.

Heavy metal pollution in aquatic environment is a rising concern and for its assessment, aquatic organisms are often used as biomonitors. The present study investigates the distribution of heavy metals (Fe, Cr, Pb, Cu, Zn, and Cd) in the surface water, surface sediment, and selected tissues of edible fish Mugil cephalus Linnaeus, collected from Kadinamkulam estuary, South India. The hierarchy of heavy metals in the estuary water is found in the order Fe > Zn > Cd > Pb > Cu > Cr, and in the surface sediments, Fe > Zn > Cd > Cu > Cr > Pb. The study shows that Pb and Cr contents in the surface water are above the permissible limits prescribed by BIS 1982 and USEPA. This study reveals that heavy metals accumulated in fish tissue is in the order of liver > gill > muscle. The metal concentrations followed the sequence Fe > Zn > Pb > Cu > Cd > Cr. The heavy metals Zn, Cd, and Pb show concentrations above the limit prescribed by the USFDA. The nearby agricultural activities and domestic waste may be the sources of high levels of heavy metals in the study area. Based on the potential human health risk indices, Mugil cephalus Linnaeus can be categorised as non-carcinogenic. The study underlines the significance of monitoring of the health status of aquatic organisms in Kadinamkulam estuary, and that of humans who may consume the estuarine fish. It is suggested that the use of pesticides and fertilizer in agricultural fields in the nearby areas be limited.

The chemical fractions of heavy metals in sediments provides important information on their mobility, bioavailability, and toxicity. This study identified the chemical fractions of six heavy metals (Pb, Zn, Cu, Cd, Cr, and Ni) in the sediments of Yeongsan River Basin, South Korea. The heavy metals were bound to sediments in the order of Pb ≈ Cd > Zn > Cu > Ni > Cr in the labile fraction, and Pb, Cd, Zn, and Cu exhibited high mobility and bioavailability. The risk assessment code (RAC), individual contamination factor (ICF), and global contamination factor (GCF) assessment results confirmed that the mobility and bioavailability of the heavy metals were relatively higher in the mid-upstream compared to downstream. The sediments in the mid-upstream had a high proportion of heavy metals bound in the labile fraction, indicating a close relationship with pollutants discharged from densely populated regions and industrial complexes.

This study investigated the effects of different concentrations of zinc (Zn) and selenium (Se) on antioxidant enzyme activity and mercury (Hg) transport/accumulation in rice seedlings under Hg stress through hydroponic experiments. The results demonstrated that combined Zn-Se application significantly enhanced physiological performance and Hg sequestration compared to individual treatments, with low-to-medium concentrations (10-40 mg/L Zn + 0.0005-0.002 mmol/L Se) exhibiting optimal efficacy. The synergistic treatment (40 mg/L Zn + 0.002 mmol/L Se) improved chlorophyll content, upregulated SOD, CAT, and GSH activities (GSH increased by 51.7%), and minimized Hg translocation and accumulation (reduced by 34.95% and 35.06%, respectively). These findings highlight the potential of Zn-Se co-application as a strategy to mitigate Hg toxicity in rice.

Microplastics (MPs) are emerging contaminants of global concern due to their potential to disrupt physiological and biochemical functions in aquatic organisms. This study investigated the effects of polyethylene (PE) microplastics on Labeo rohita, a commercially important freshwater carp. Fingerlings (25 ± 2 g) were exposed to 0 (control), 1, 3, and 5 mg/L PE microplastics for 60 days, followed by a 30-day recovery period in clean water. Microplastic accumulation was quantified in gill, liver, and intestine, and impacts on tissue biochemistry (carbohydrates, proteins, lipids), antioxidant enzyme activities (SOD, CAT, GST), micronucleus formation, and behavioural responses were assessed. Results revealed dose-dependent reductions in carbohydrate, protein, and lipid levels, significant decreases in antioxidant enzyme activities, and a marked increase in micronuclei frequency at higher concentrations, indicating oxidative stress and genotoxicity. During recovery, proteins and carbohydrates largely returned to baseline, whereas lipid content, antioxidant enzymes, and micronucleus frequencies showed partial restoration, especially at higher exposure levels. These findings demonstrate that PE microplastics induce metabolic disruption, oxidative stress, and genomic instability in L. rohita, with recovery being incomplete at elevated concentrations, highlighting potential ecological and aquaculture risks.